The present invention relates to a method and device for generating distinguishable signals and a method of distinguishing signals of similar shape.
In electronic systems where two or more output channels of a signal generator are connected to two or more input channels of a receiver, for instance an electronic control unit being supplied with sensor signals, it is a common problem that the channels get mixed up due to a cross-wired connection between the signal generator and the electronic control unit. If the signals indicate different states or situations, such a mix up of channels can result in the application of inappropriate control algorithms by the electronic control unit due to faulty information.
One example for a devastating result of a cross-wired connection between such a signal generator and an electronic control unit is within an automotive vehicle, where a steering wheel sensor detects the turn of a steering wheel, i.e. the direction and the angle. During a right turn, for instance, the wheels on the right side of the vehicle are on the inner side of the curve and therefore have a shorter way to go through the curve. As a result they are supposed to be slower than the wheels on the left side of the vehicle. Should the steering angle sensor have its output channels switched and connected to the wrong input channels of the electronic control unit, then the electronic control unit would receive a faulty signal code and possibly recognize a left turn. During braking, the information about the individual wheel speeds is important for an anti-lock brake system. If the system determines that the vehicle is going through a left turn and, during braking, the wheels on the right vehicle side turn at a lower rate than on the left vehicle side, then the conclusion would be that the wheels on the right vehicle side are locking or at least have a very high wheel slip. The anti-lock control system would interfere with the braking operation, but only because of faulty information about the direction of the turn.
The object of the present invention is therefore to create a system where two signals bearing different information can be distinguished and identified in a fail-safe manner.